Consensus report. Periodontal diseases: pathogenesis and microbial factors

Bactericidal effect of visible light in the presence of erythrosine on Porphyromonas gingivalis and Fusobacterium nucleatum compared with diode laser, an in vitro study

OBJECTIVES

Recently, photodynamic therapy (PDT) has been introduced as a new modality in oral bacterial decontamination. Besides, the ability of laser irradiation in the presence of photosensitizing agent to lethal effect on oral bacteria is well documented. Current research aims to evaluate the effect of photodynamic killing of visible blue light in the presence of plaque disclosing agent erythrosine as photosensitizer on Porphyromonas gingivalis associated with periodontal bone loss and Fusobacterium nucleatum associated with soft tissue inflammation, comparing with the near-infrared diode laser.

MATERIALS AND METHODS

Standard suspension of P. gingivalis and F. nucleatum were exposed to Light Emitting Diode (LED) (440-480 nm) used to photopolymerize composite resine dental restoration in combination with erythrosine (22 µm) up to 5 minutes. Bacterial sample were also exposed to a near-infrared diode laser (wavelength, 830 nm), using identical irradiation parameters for comparison. Bacterial samples from each treatment groups (radiation-only group, erythrosine-only group and light or laser with erythrosine group) were subcultured onto the surface of agar plates. Survival of these bacteria was determined by counting the number of colony forming units (CFU) after incubation.

RESULTS

Exposure to visible blue light and diode laser in conjugation with erythrosine significantly reduced both species examined viability, whereas erythrosine-treated samples exposed to visible light suggested a statically meaningful differences comparing to diode laser. In addition, bactericidal effect of visible light or diode laser alone on P. gingivalis as black-pigmented bacteria possess endogenous porphyrins was noticeably.

CONCLUSION

Our result suggested that visible blue light source in the presence of plaque disclosing agent erythrosine could can be consider as potential approach of PDT to kill the main gram-negative periodontal pathogens. From a clinical standpoint, this regimen could be established as an additional minimally invasive antibacterial treatment of plaque induced periodontal pathologies.

Association between tobacco use and the upper gastrointestinal microbiome among Chinese men

PURPOSE

Tobacco causes many adverse health conditions and may alter the upper gastrointestinal (UGI) microbiome. However, the few studies that studied the association between tobacco use and the microbiome were small and underpowered. Therefore, we investigated the association between tobacco use and the UGI microbiome in Chinese men.

METHODS

We included 278 men who underwent esophageal cancer screening in Henan Province, China. Men were categorized as current, former, or never smokers from questionnaire data. UGI tract bacterial cells were characterized using the Human Oral Microbial Identification Microarray. Counts of unique bacterial species and genera estimated alpha diversity. For beta diversity, principal coordinate (PCoA) vectors were generated from an unweighted UniFrac distance matrix. Polytomous logistic regression models were used for most analyses.

RESULTS

Of the 278 men in this study, 46.8% were current smokers and 12.6% were former smokers. Current smokers tended to have increased alpha diversity (mean 42.3 species) compared to never smokers (mean 38.9 species). For a 10 species increase, the odds ratio (OR) for current smoking was 1.29 (95% CI 1.04-1.62). Beta diversity was also associated with current smoking. The first two PCoA vectors were strongly associated with current smoking (PCoA1 OR 0.66; 95% CI 0.51-0.87; PCoA2 OR 0.73; 95% CI 0.56-0.95). Furthermore, Dialister invisus and Megasphaera micronuciformis were more commonly detected in current smokers than in never smokers.

CONCLUSIONS

Current smoking was associated with both alpha and beta diversity in the UGI tract. Future work should consider how the UGI microbiome is associated with smoking-related diseases.

An estimate of pocket closure and avoided needs of surgery after scaling and root planing with systemic antibiotics: a systematic review

BACKGROUND

Relevant benefits of adjunctive medication of antibiotica after conventional root surface debridement in terms of enhanced pocket depth (PD) reduction have been shown. However, means and standard deviations of enhanced reductions are difficult to translate into clinical relevant treatment outcomes such as pocket resolution or avoidance of additional surgical interventions. Accordingly, the aim of this systematic review was to calculate odds ratios for relevant cut-off values of PD after mechanical periodontal treatment with and without antibiotics, specifically the combination of amoxicilline and metronidazol, from published studies. As clinical relevant cut-off values "pocket closure" for PD ≤ 3mm and "avoidance of surgical intervention" for PD ≤ 5 mm were determined.

METHODS

The databases PubMed, Embase and Central were searched for randomized clinical studies assessing the beneficial effect of the combination of amoxicillin and metronidazole after non-surgical mechanical debridement. Titles, abstracts and finally full texts were scrutinized for possible inclusion by two independent investigators. Quality and heterogeneity of the studies were assessed and the study designs were examined. From published means and standard deviations for PD after therapy, odds ratios for the clinically relevant cut-off values were calculated using a specific statistical approach.

RESULTS

Meta-analyses were performed for the time points 3 and 6 month after mechanical therapy. Generally, a pronounced chance for pocket closure from 3 to 6 months of healing was shown. The administration of antibiotics resulted in a 3.55 and 4.43 fold higher probability of pocket closure after 3 and 6 months as compared to mechanical therapy alone. However, as the estimated risk for residual pockets > 5 mm was 0 for both groups, no odds ratio could be calculated for persistent needs for surgery. Generally, studies showed a moderate to high quality and large heterogeneity regarding treatment protocol, dose of antibiotic medication and maintenance.

CONCLUSION

With the performed statistical approach, a clear benefit in terms of an enhanced chance for pocket closure by co-administration of the combination of amoxicillin and metronidazole as an adjunct to non-surgical mechanical periodontal therapy has been shown. However, data calculation failed to show a benefit regarding the possible avoidance of surgical interventions.

Non-surgical periodontal therapy: An update on current evidence

Periodontal disease is an inflammatory condition that involves a complex interaction between pathogenic bacteria, environmental and acquired factors and host related factors. Till recently periodontal treatment was directed primarily towards reduction of bacterial load by subgingival debridement of root surfaces and modification of environmental risk factors. The current paradigm of periodontal disease stresses greater role of host-mediated inflammatory response in tissue destruction characteristic of periodontal disease. Various therapeutic modalities have been developed adjuvant to mechanical periodontal therapy. The use of laser and photodynamic therapy show great promise but their effectiveness has still not been conclusively proven. Chemotherapeutic agents, either systemic and local antimicrobials or host modulating drugs, played pivotal role in better and more predictable management of periodontal disease. The present review focuses on the best available evidence, for the current management of the chronic periodontal patients, gathered from systematic reviews and meta-analysis of mechanical non surgical periodontal therapy (NSPT) (subgingival debridement, laser therapy and photodynamic therapy) and the adjunctive chemotherapeutic approaches such as systematic and local antibiotics and antiseptics, subgingival pocket irrigation and host modulation therapies. The review also attempts to briefly introduce future developments in some of these modalities. At the end, the review summarizes the analysis of the current evidence that suggests that thorough subgingival debridement remains the mainstay of NSPT and that adjunct use of chemotherapeutic agents may offer better management of clinical parameters in periodontitis patients.

Characterization and serotype distribution of Aggregatibacter actinomycetemcomitans isolated from a population of periodontitis patients in Spain

OBJECTIVE

There is no study characterizing the variability of Aggregatibacter actinomycetemcomitans isolates in periodontitis patients in Spain. It is therefore the aim of this investigation to study the serotype distribution of A. actinomycetemcomitans strains isolated from periodontitis patients in Spain. The polymorphism of the genes that codifies the leukotoxin and the operon of the cytolethal-distending toxin (cdt) will also be investigated.

DESIGN

From a total of 701 patients samples, 40 A. actinomycetemcomitans-positive periodontitis patients were included in the study (mean age 45.3, 62.5% females) and their clinical periodontal status was assessed. On average, 1-3 isolates from each patient were sub-cultured and characterized by PCR.

RESULTS

Using culture the prevalence of A. actinomycetemcomitans was 5.7%. The most frequent serotype was "b", being 30 patients infected by a unique serotype, while 7 patients showed co-colonization, mostly with serotypes "a" and "b". From the 79 pure isolates obtained, 24 were from serotype "a", 30 from serotype "b", 12 from serotype "c" and 4 from serotype "d". Further characterization of these samples showed that none of these 79 isolates demonstrated the 530-bp deletion in the leukotoxin's promoter region that characterizes the JP2 strain. Conversely 65.8% of the isolates were cdt+.

CONCLUSIONS

The most common serotypes were "a" and "b", being serotype "b" the most prevalent in mono-colonization, while serotypes "e" and "f" were not detected. In the majority of samples, operon that codifies the cdt (65.8%) and the genes responsible for the codification of leukotoxin (100%) were found. None of the isolates were JP2 strains.

Relationship between expression of human gingival beta-defensins and levels of periodontopathogens in subgingival plaque

BACKGROUND AND OBJECTIVE

Human beta-defensins (hBDs) are a group of antimicrobial peptides important in epithelial innate immunity, and their differential expression is associated with periodontal diseases. The aim of this study was to explore relationships among hBDs, total subgingival bacteria and periodontopathogens in healthy subjects and in patients with chronic periodontitis.

MATERIAL AND METHODS

The periodontal clinical parameters of 29 healthy subjects and 25 patients with chronic periodontitis were recorded. The relative expression of hBD1, hBD2 and hBD3 genes in gingival biopsies was measured using real-time PCR. The numbers of total bacteria and of Treponema denticola, Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Fusobacterium nucleatum and Tannerella forsythia in subgingival plaque were quantified by real-time PCR. Data were analyzed using the Mann-Whitney U-test and Spearman's rank correlation test.

RESULTS

No significant differences in expression of the hBD genes were found between the group of healthy subjects and the group of patients with chronic periodontitis. Total bacteria and T. denticola were detected in all participants. F. nucleatum and T. forsythia were detected in all patients with chronic periodontitis and in 86.21% and 51.72%, respectively, of healthy volunteers. P. gingivalis and A. actinomycetemcomitans were detected in 24.14% and 17.24%, respectively, of the healthy group and in 84.00% and 12.00%, respectively, of the chronic periodontitis group. The prevalence of all bacteria, except A. actinomycetemcomitans, was significantly higher in the group of patients with chronic periodontitis than in the group of healthy subjects (p < 0.05). A significant, negative correlation was observed between total bacteria and hBD-2 (r = -0.384, p = 0.011). Upon analyzing the data in different groups, total bacteria and hBD-2 were significantly correlated (r = -0.492, p = 0.026) only in the group of healthy subjects.

CONCLUSION

The negative correlations between hBD-2 and total bacteria, especially in the group of healthy subjects, indicate that hBDs may play an important role by limiting an increase of bacterial load at the initial stage of periodontitis.

Lessons learned and unlearned in periodontal microbiology

Periodontal diseases are initiated by bacterial species living in polymicrobial biofilms at or below the gingival margin and progress largely as a result of the inflammation elicited by specific subgingival species. In the past few decades, efforts to understand the periodontal microbiota have led to an exponential increase in information about biofilms associated with periodontal health and disease. In fact, the oral microbiota is one of the best-characterized microbiomes that colonize the human body. Despite this increased knowledge, one has to ask if our fundamental concepts of the etiology and pathogenesis of periodontal diseases have really changed. In this article we will review how our comprehension of the structure and function of the subgingival microbiota has evolved over the years in search of lessons learned and unlearned in periodontal microbiology. More specifically, this review focuses on: (i) how the data obtained through molecular techniques have impacted our knowledge of the etiology of periodontal infections; (ii) the potential role of viruses in the etiopathogenesis of periodontal diseases; (iii) how concepts of microbial ecology have expanded our understanding of host-microbe interactions that might lead to periodontal diseases; (iv) the role of inflammation in the pathogenesis of periodontal diseases; and (v) the impact of these evolving concepts on therapeutic and preventive strategies to periodontal infections. We will conclude by reviewing how novel systems-biology approaches promise to unravel new details of the pathogenesis of periodontal diseases and hopefully lead to a better understanding of their mechanisms.

Learned and unlearned concepts in periodontal diagnostics: a 50-year perspective

In the past 50 years, conceptual changes in the field of periodontal diagnostics have paralleled those associated with a better scientific understanding of the full spectrum of processes that affect periodontal health and disease. Fifty years ago, concepts regarding the diagnosis of periodontal diseases followed the classical pathology paradigm. It was believed that the two basic forms of destructive periodontal disease were chronic inflammatory periodontitis and 'periodontosis'- a degenerative condition. In the subsequent 25 years it was shown that periodontosis was an infection. By 1987, major new concepts regarding the diagnosis and pathogenesis of periodontitis included: (i) all cases of untreated gingivitis do not inevitably progress to periodontitis; (ii) progression of untreated periodontitis is often episodic; (iii) some sites with untreated periodontitis do not progress; (iv) a rather small population of specific bacteria ('periodontal pathogens') appear to be the main etiologic agents of chronic inflammatory periodontitis; and (v) tissue damage in periodontitis is primarily caused by inflammatory and immunologic host responses to infecting agents. The concepts that were in place by 1987 are still largely intact in 2012. However, in the decades to come, it is likely that new information on the human microbiome will change our current concepts concerning the prevention, diagnosis and treatment of periodontal diseases.

Antagonistic effect of protein extracts from Streptococcus sanguinis on pathogenic bacteria and fungi of the oral cavity

An antibacterial substance from Streptococcus sanguinis (S. sanguinis) is known to have an inhibitory effect on putative periodontal pathogens, but its inhibitory effect on pathogens of oral candidiasis is unknown. In this study, intracellular and exocrine proteins were extracted from S. sanguinis. The antagonistic effect of the protein extracts on Prevotella intermedia (P. intermedia) and Porphyromonas gingivalis (P. gingivalis) was detected by a well-plate technique, and the effects of the protein extracts on biofilms formed by these bacteria were evaluated by confocal laser scanning microscopy. The antagonistic effect of the protein extracts on pathogenic fungi was investigated using Candida albicans (C. albicans) and Candida tropicalis (C. tropicalis). The growth curves of C. albicans and C. tropicalis were determined from ultraviolet absorption measurements, their morphological changes following treatment were observed by optical microscopy and scanning electron microscopy, and the effects of the protein extracts on the thickness of their biofilms and the distribution of dead/live bacteria within the biofilms were detected by confocal laser scanning microscopy. The results showed significant inhibitory effects of the intracellular proteins extracted from S. sanguinis on pathogenic bacteria (P. intermedia and P. gingivalis), fungi (C. albicans and C. tropicalis) and the biofilms formed by them. Furthermore, the growth curves and morphology of C. albicans and C. tropicalis were altered following treatment with the intracellular proteins, resulting in disc-like depressions in the surfaces of the fungal spores and mycelia. By contrast, the exocrine proteins demonstrated no significant inhibitory effect on the pathogenic bacteria, fungi and the biofilms formed by them. Thus, it may be concluded that intracellular proteins of S. sanguinis have antibacterial activity and exert an antagonistic effect on certain pathogenic bacteria and fungi of the oral cavity.

In vitro-activity of oily calcium hydroxide suspension on microorganisms as well as on human alveolar osteoblasts and periodontal ligament fibroblasts

Background

Findings from animal and human studies have indicated that an oily calcium hydroxide suspension (OCHS) may improve early wound healing in the treatment of periodontitis. Calcium hydroxide as the main component is well known for its antimicrobial activity, however at present the effect of OCHS on the influence of periodontal wound healing/regeneration is still very limited. The purpose of this in vitro study was to investigate the effect of OCHS on periodontopathogenic bacteria as well as on the attachment and proliferation of osteoblasts and periodontal ligament fibroblasts.

Methods

Human alveolar osteoblasts (HAO) and periodontal ligament (PDL) fibroblasts were cultured on 3 concentrations of OCHS (2.5, 5 and 7.5 mg). Adhesion and proliferation were counted up to 48 h and mineralization was assayed after 1 and 2 weeks. Furthermore potential growth inhibitory activity on microorganisms associated with periodontal disease (e.g. Porphyromonas gingivalis, Tannerella forsythia, Aggregatibacter actinomycetemcomitans) as well as the influence of periodontopathogens and OCHS on the HAO and PDL fibroblasts counts were determined.

Results

More than a 2-fold increase in adherent HAO cells was observed at 4 h following application of OCHS when compared to the control group (p = 0.007 for 2.5 mg). Proliferation of HAO cells at 48 h was stimulated by moderate concentrations (2.5 mg; 5 mg) of OCHS (each p < 0.001), whereas a high concentration (7.5 mg) of OCHS was inhibitory (p = 0.009). Mineralization was observed only for HAO cells treated with OCHS. OCHS did not exert any positive effect on attachment or proliferation of PDL fibroblasts. Although OCHS did not have an antibacterial effect, it did positively influence attachment and proliferation of HAO cells and PDL fibroblasts in the presence of periodontopathogens.

Conclusions

The present data suggests that OCHS promotes osteoblast attachment, proliferation and mineralization in a concentration-dependent manner and results are maintained in the presence of periodontal pathogens.

Community interactions of oral streptococci

It is now clear that the most common oral diseases, dental caries and periodontitis, are caused by mixed-species communities rather than by individual pathogens working in isolation. Oral streptococci are central to these disease processes since they are frequently the first microorganisms to colonize oral surfaces and they are numerically the dominant microorganisms in the human mouth. Numerous interactions between oral streptococci and other bacteria have been documented. These are thought to be critical for the development of mixed-species oral microbial communities and for the transition from oral health to disease. Recent metagenomic studies are beginning to shed light on the co-occurrence patterns of streptococci with other oral bacteria. Refinements in microscopy techniques and biofilm models are providing detailed insights into the spatial distribution of streptococci in oral biofilms. Targeted genetic manipulation is increasingly being applied for the analysis of specific genes and networks that modulate interspecies interactions. From this work, it is clear that streptococci produce a range of extracellular factors that promote their integration into mixed-species communities and enable them to form social networks with neighboring taxa. These "community integration factors" include coaggregation-mediating adhesins and receptors, small signaling molecules such as peptides or autoinducer-2, bacteriocins, by-products of metabolism including hydrogen peroxide and lactic acid, and a range of extracellular enzymes. Here, we provide an overview of various types of community interactions between oral streptococci and other microorganisms, and we consider the possibilities for the development of new technologies to interfere with these interactions to help control oral biofilms.

Haplotype analysis of interleukin-8 gene polymorphisms in chronic and aggressive periodontitis

Objectives. Periodontitis is an inflammatory disease characterized by connective tissue loss and alveolar bone destruction. Interleukin-8 (IL8) is important in the regulation of the immune response. The aim of this study was to analyze four polymorphisms in the IL8 gene in relation to chronic (CP) and aggressive (AgP) periodontitis. Methods. A total of 492 unrelated subjects were included in this case-control association study. Genomic DNA of 278 patients with CP, 58 patients with AgP, and 156 controls were genotyped, using the 5′ nuclease TaqMan assay, for IL8 (rs4073, rs2227307, rs2227306, and rs2227532) gene polymorphisms. Subgingival bacterial colonization was investigated by the DNA-microarray detection kit in a subgroup of subjects (N = 247). Results. Allele and genotype frequencies of all investigated IL8 polymorphisms were not significantly different between the subjects with CP and/or AgP and controls (P > 0.05). Nevertheless, the A(−251)/T(+396)/T(+781) and T(−251)/G(+396)/C(+781) haplotypes were significantly less frequent in patients with CP (2.0% versus 5.1%, P < 0.02, OR = 0.34, 95% CI: 0.15–0.78, resp., 2.0% versus 4.5%, P < 0.05, OR = 0.41, 95% CI: 0.18–0.97) than in controls. Conclusions. Although none of the investigated SNPs in the IL8 gene was individually associated with periodontitis, some haplotypes can be protective against CP in the Czech population.

Antibacterial activity of moxifloxacin on bacteria associated with periodontitis within a biofilm

The activity of moxifloxacin was compared with ofloxacin and doxycycline against bacteria associated with periodontitis within a biofilm (single strain and mixed population) in vitro. MICs and minimal bactericidal concentrations (MBCs) of moxifloxacin, ofloxacin and doxycyline were determined against single strains and mixed populations in a planktonic state. Single-species biofilms of two Porphyromonas gingivalis and two Aggregatibacter actinomycetemcomitans strains and a multispecies biofilm consisting of 12 species were formed for 3 days. The minimal biofilm eradication concentrations (MBECs) were determined after exposing the biofilms to the antibacterials (0.002-512 µg ml(-1)) for 18 h, addition of nutrient broth for 3 days and subsequent subcultivation. Photographs were taken using confocal laser-scanning microscopy and scanning electron microscopy. The MICs and MBCs did not differ between ofloxacin and moxifloxacin against A. actinomycetemcomitans, whilst moxifloxacin was more active than the other tested antibacterials against anaerobes and the mixed population. The single-species biofilms were eradicated by moderate concentrations of the antibacterials, and the lowest MBECs were always found for moxifloxacin (2-8 µg ml(-1)). MBECs against the multispecies biofilms were 128, >512 and >512 µg ml(-1) for moxifloxacin, ofloxacin and doxycycline, respectively. In summary, moxifloxacin in a topical formulation may have potential as an adjunct to mechanical removal of the biofilms.

Determination of periodontopathogens in patients with Cri du chat syndrome

Objectives: Cri du chat syndrome is a genetic alteration associated with some oral pathologies. However, it has not been described previously any clinical relationship between the periodontal disease and the syndrome. The purpose of this comparative study was to compare periodontopathogenic flora in a group with Cri du chat syndrome and another without the síndrome, to assess a potential microbiological predisposition to suffer a periodontitis. Study Design: The study compared nineteen subjects with Cri du chat Syndrome with a control group of nineteen patients without it. All patients were clinically evaluated by periodontal probing, valuing the pocket depth, the clinical attachmente level and bleeding on probing. There were no significant differences between both groups. Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Tannerella forsythia and Treponema denticola were detected by multiplex-PCR using 16S rDNA (microIDENT). Results: When A. actinomycetemcomitans, P. gingivalis, P. intermedia and T. denticola were compared, no statistically significant differences were found between the two groups (p>0.05). The value of T. forsythia was significantly higher for Cri du chat syndrome (31.6%) than for the control group (5.3%). The odds ratio for T. forsythia was 8.3. Conclusions: In the present study T. forsythia is associated with Cri du chat syndrome subjects and not with healthy subjects.

Key words:Cri du Chat syndrome, periodontal health, microbiology, special care dentistry.

Changes in clinical and microbiological periodontal profiles relate to progression of carotid intima-media thickness: the Oral Infections and Vascular Disease Epidemiology study

Background

No prospective studies exist on the relationship between change in periodontal clinical and microbiological status and progression of carotid atherosclerosis.

Methods and Results

The Oral Infections and Vascular Disease Epidemiology Study examined 420 participants at baseline (68±8 years old) and follow‐up. Over a 3‐year median follow‐up time, clinical probing depth (PD) measurements were made at 75 766 periodontal sites, and 5008 subgingival samples were collected from dentate participants (average of 7 samples/subject per visit over 2 visits) and quantitatively assessed for 11 known periodontal bacterial species by DNA‐DNA checkerboard hybridization. Common carotid artery intima‐medial thickness (CCA‐IMT) was measured using high‐resolution ultrasound. In 2 separate analyses, change in periodontal status (follow‐up to baseline), defined as (1) longitudinal change in the extent of sites with a ≥3‐mm probing depth (Δ%PD≥3) and (2) longitudinal change in the relative predominance of bacteria causative of periodontal disease over other bacteria in the subgingival plaque (Δetiologic dominance), was regressed on longitudinal CCA‐IMT progression adjusting for age, sex, race/ethnicity, diabetes, smoking status, education, body mass index, systolic blood pressure, and low‐density lipoprotein cholesterol and high‐density lipoprotein cholesterol. Mean (SE) CCA‐IMT increased during follow‐up by 0.139±0.008 mm. Longitudinal IMT progression attenuated with improvement in clinical or microbial periodontal status. Mean CCA‐IMT progression varied inversely across quartiles of longitudinal improvement in clinical periodontal status (Δ%PD≥3) by 0.18 (0.02), 0.16 (0.01), 0.14 (0.01), and 0.07 (0.01) mm (P for trend<0.0001). Likewise, mean CCA‐IMT increased by 0.20 (0.02), 0.18 (0.02), 0.15 (0.02), and 0.12 (0.02) mm (P<0.0001) across quartiles of longitudinal improvement in periodontal microbial status (Δetiologic dominance).

Conclusion

Longitudinal improvement in clinical and microbial periodontal status is related to a decreased rate of carotid artery IMT progression at 3‐year average follow‐up.

Quantitative analysis of periodontal pathogens present in the saliva of geriatric subjects

PURPOSE

At present, information regarding periodontal disease in geriatric patients is scarce. The purpose of this study was to quantify the periodontal pathogens present in the saliva of Korean geriatric patients and assess the relationship between the bacterial levels and the periodontal condition.

METHODS

Six putative periodontal pathogens were quantified by using a real-time polymerase chain reaction assay in geriatric patient groups (>60 years) with mild chronic periodontitis (MCP), moderate chronic periodontitis (MoCP), and severe chronic periodontitis (SCP). The copy numbers of Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum, and Prevotella intermedia were measured.

RESULTS

It was found that the bacterial copy numbers increased as the severity of the disease increased from MCP to SCP, except for P. intermedia. For P. intermedia, it was found that samples in the MCP group yielded the largest amount. It was also found that the quantities of P. gingivalis, T. forsythia, and T. denticola, the so-called "red complex" bacteria, were lower than those of F. nucleatum, A. actinomycetemcomitans, and P. intermedia in all of the samples.

CONCLUSIONS

Collectively, the results of this study suggest that the levels of P. gingivalis, T. forsythia, F. nucleatum, and T. denticola present in saliva are associated with the severity of periodontal disease in geriatric patients.

Influence of periodontal disease, Porphyromonas gingivalis and cigarette smoking on systemic anti-citrullinated peptide antibody titres

BACKGROUND

Anti-citrullinated protein antibody (ACPA) responses may precede clinical onset of rheumatoid arthritis. Porphyromonas gingivalis peptidylarginine deiminase can citrullinate proteins possibly inducing autoimmunity in susceptible individuals.

AIM

To determine whether periodontitis, carriage of P. gingivalis, smoking and periodontal therapy influence ACPA titres.

METHODS

Serum and plaque samples were collected from 39 periodontitis patients before and after non-surgical periodontal treatment, and from 36 healthy subjects. Carriage of P. gingivalis was determined by PCR of plaque DNA. ACPA was determined by anti-cyclic citrullinated peptide (CCP) enzyme-linked immunosorbent assay (ELISA). Anti-P. gingivalis titres were determined by ELISA.

RESULTS

Untreated periodontitis patients had higher anti-CCP antibody titres than healthy controls [three patients (8%) greater than manufacturer suggested assay diagnostic threshold (5 Assay Units/AU) versus none (0%); mean ± SEM: 1.37 ± 0.23 versus 0.40 ± 0.10 AU, p < 0.0001]. Periodontitis patients who smoked demonstrated lower anti-P. gingivalis (15956 ± 4385 versus 2512 ± 1290 Units/ml, p < 0.05), but similar anti-CCP than non-smoking periodontitis patients (smokers: 1.31 ± 0.35; non-smokers: 1.41 ± 0.32 AU). Healthy smokers demonstrated elevated anti-CCP titres (0.75 ± 0.19 AU), at levels between healthy non-smokers (0.15 ± 0.05 AU) and non-smoker periodontitis patients. Six months after periodontal treatment, there were significant reductions in anti-CCP (non-smokers p < 0.05) and anti-P. gingivalis (all participants p < 0.01).

CONCLUSION

In subjects with periodontitis, P. gingivalis infection may be responsible for inducing autoimmune responses that characterize rheumatoid arthritis.

Evaluation of antioxidant enzymes activity and malondialdehyde levels in patients with chronic periodontitis and diabetes mellitus

BACKGROUND

The aim of this study is to investigate the impact of diabetes, a known risk factor for periodontitis, on activities of antioxidant enzymes superoxide dismutase (SOD), glutathione reductase (GR), and catalase (CAT) as well as levels of free radical damage marker malondialdehyde (MDA) in blood and saliva of individuals with chronic periodontitis (CP).

METHODS

Sixty patients with CP (30 patients with type 2 diabetes mellitus [DMCP] and 30 systemically healthy patients [CP]) and 60 periodontally healthy individuals (30 patients with type 2 diabetes mellitus and 30 systemically healthy patients [PH]) were included in this study. After clinical measurements, blood and saliva samples were collected. SOD, GR, and CAT activities in red blood cell lysate and saliva and MDA levels in plasma and saliva samples were spectrophotometrically assayed. An analysis of variance test followed by a post hoc test was used to compare the intragroup and intergroup variances among the study groups.

RESULTS

MDA levels in both the periodontitis groups were higher than in the periodontally healthy groups, but the difference between the CP and DMCP groups did not reach statistical significance (P >0.05). There was a highly significant difference between the CP and PH groups for all the enzymes studied except for SOD in blood. Only salivary SOD and GR activities were significantly different in the CP and DMCP groups.

CONCLUSIONS

This study favors the role of oxidative stress in both diabetes and periodontitis. It shows that the compensatory mechanism of the body is partially collapsed because of excessive production of free radicals during periodontitis and is not able to cope with increased free radical generation attributable to diabetes, thereby worsening the situation.

Predictive, preventive, personalised and participatory periodontology: 'the 5Ps age' has already started

An impressive progress in dentistry has been recorded in the last decades. In order to reconsider guidelines in dentistry, it is required to introduce new concepts of personalised patient treatments: the wave of predictive, preventive and personalised medicine is rapidly incoming in dentistry. Worldwide dentists have to make a big cultural effort in changing the actual 'reactive' therapeutic point of view, belonging to the last century, into a futuristic 'predictive' one. The first cause of tooth loss in industrialised world is periodontitis, a Gram-negative anaerobic infection whose pathogenesis is genetically determined and characterised by complex immune reactions. Chairside diagnostic tests based on saliva, gingival crevicular fluid and cell sampling are going to be routinely used by periodontists for a new approach to the diagnosis, monitoring, prognosis and management of periodontal patients. The futuristic '5Ps' (predictive, preventive, personalised and participatory periodontology) focuses on early integrated diagnosis (genetic, microbiology, host-derived biomarker detection) and on the active role of the patient in which networked patients will shift from being mere passengers to responsible drivers of their health. In this paper, we intend to propose five diagnostic levels (high-tech diagnostic tools, genetic susceptibility, bacterial infection, host response factors and tissue breakdown-derived products) to be evaluated with the intention to obtain a clear picture of the vulnerability of a single individual to periodontitis in order to organise patient stratification in different categories of risk. Lab-on-a-chip (LOC) technology may soon become an important part of efforts to improve worldwide periodontal health in developed nations as well as in the underserved communities, resource-poor areas and poor countries. The use of LOC devices for periodontal inspection will allow patients to be screened for periodontal diseases in settings other than the periodontist practice, such as at general practitioners, general dentists or dental hygienists. Personalised therapy tailored with respect to the particular medical reality of the specific stratified patient will be the ultimate target to be realised by the 5Ps approach. A long distance has to be covered to reach the above targets, but the pathway has already been clearly outlined.

Subgingival microbial profiles as diagnostic markers of destructive periodontal diseases: a clinical epidemiology study

AIMS

To describe the subgingival microbial profiles of the major putative periodontal pathogens and investigate their role as diagnostic markers for destructive periodontal diseases in an untreated and isolated population.

MATERIALS AND METHODS

The source population consisted of all subjects aged ≥ 12 years in an isolated Brazilian population. An interview and a full-mouth clinical examination were conducted and subgingival plaque samples were obtained from four sites per subject. PCR analyses were used to identify the following micro-organisms: Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia, Prevotella intermedia and Campylobacter rectus.

RESULTS

Among the 214 clinically examined subjects (81% response), 170 of the 195 dentate subjects provided plaque samples. Two subgingival microbial profiles were identified: absence of all micro-organisms but Campylobacter rectus or co-occurrence of Tannerella forsythia and Porphyromonas gingivalis. Using a combination of microbiological and interview information, the smallest overall misclassification in the diagnosis of extensive clinical attachment loss ≥ 5 mm was 8.8% (4.7% of non-cases and 22% of cases), but this was not different from the 7.6% (2.3% non-cases and 24.4% cases) obtained using clinical and interview information (p = 0.292).

CONCLUSION

Specific microbial profiles could be identified in this isolated population. They did not result in significant superior diagnostic accuracy when compared to traditional clinical markers.

Association between selected oral pathogens and gastric precancerous lesions

We examined whether colonization of selected oral pathogens is associated with gastric precancerous lesions in a cross-sectional study. A total of 119 participants were included, of which 37 were cases of chronic atrophic gastritis, intestinal metaplasia, or dysplasia. An oral examination was performed to measure periodontal indices. Plaque and saliva samples were tested with real-time quantitative PCR for DNA levels of pathogens related to periodontal disease (Porphyromonas gingivalis, Tannerella forsythensis, Treponema denticola, Actinobacillus actinomycetemcomitans) and dental caries (Streptococcus mutans and S. sobrinus). There were no consistent associations between DNA levels of selected bacterial species and gastric precancerous lesions, although an elevated but non-significant odds ratio (OR) for gastric precancerous lesions was observed in relation to increasing colonization of A. actinomycetemcomitans (OR = 1.36 for one standard deviation increase, 95% Confidence Interval = 0.87-2.12), P. gingivalis (OR = 1.12, 0.67-1.88) and T. denticola (OR = 1.34, 0.83-2.12) measured in plaque. To assess the influence of specific long-term infection, stratified analyses by levels of periodontal indices were conducted. A. actinomycetemcomitans was significantly associated with gastric precancerous lesions (OR = 2.51, 1.13-5.56) among those with ≥ median of percent tooth sites with PD ≥ 3 mm, compared with no association among those below the median (OR = 0.86, 0.43-1.72). A significantly stronger relationship was observed between the cumulative bacterial burden score of periodontal disease-related pathogens and gastric precancerous lesions among those with higher versus lower levels of periodontal disease indices (p-values for interactions: 0.03-0.06). Among individuals with periodontal disease, high levels of colonization of periodontal pathogens are associated with an increased risk of gastric precancerous lesions.

Perinatal periodontal disease reduces social behavior in male offspring

OBJECTIVE

Our objective was to verify whether prenatal maternal periodontitis is a risk factor for the development of central nervous system disorders in rats.

METHODS

Periodontitis was induced by placing a ligature around the upper and lower first molars in 9 female Wistar rats (experimental group); 9 rats were left unligated (control group). The maternal general activity in an open field was observed on gestational day (GD) 0, GD 4, and GD 14, and the maternal performance was assessed on the second day after birth. The pups' play behavior was assessed on postnatal day 30. The relative level of reelin was measured in the frontal cortex by real-time PCR analysis.

RESULTS

The results showed that, compared with the control group, (1) the general activity in female rats with periodontitis was decreased, (2) the maternal performance of these rats was not modified by periodontitis, (3) the play behavior of pups from dams with periodontitis was decreased, and (4) there were no differences in the frontal cortex reelin levels of pups from dams with periodontitis.

CONCLUSIONS

We conclude that pre- and postnatal periodontitis induces maternal sickness behavior and reduces the pups' play behavior without interference with frontal cortex reelin expression.

Bacterial adhesion and colonization differences between zirconia and titanium implant abutments: an in vivo human study

Purpose

Several parameters have been described for determining the success or failure of dental implants. The surface properties of transgingival implant components have had a great impact on the long-term success of dental implants. The purpose of this study was to compare the tendency of two periodontal pathogens to adhere to and colonize zirconia abutments and titanium alloys both in hard surfaces and soft tissues.

Methods

Twelve patients participated in this study. Three months after implant placement, the abutments were connected. Five weeks following the abutment connections, the abutments were removed, probing depth measurements were recorded, and gingival biopsies were performed. The abutments and gingival biopsies taken from the buccal gingiva were analyzed using real-time polymerase chain reaction to compare the DNA copy numbers of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, and total bacteria. The surface free energy of the abutments was calculated using the sessile water drop method before replacement. Data analyses used the Mann Whitney U-test, and P-values below 0.05 find statistical significance.

Results

The present study showed no statistically significant differences between the DNA copy numbers of A. actinomycetemcomitans, P. gingivalis, and total bacteria for both the titanium and zirconia abutments and the biopsies taken from their buccal gingiva. The differences between the free surface energy of the abutments had no influence on the microbiological findings.

Conclusions

Zirconia surfaces have comparable properties to titanium alloy surfaces and may be suitable and safe materials for the long-term success of dental implants.

Clearance of topically-applied PVP-iodine as a solution or gel in periodontal pockets in men

OBJECTIVES

The aim of the study was to investigate the clearance of PVP-iodine applied as a gel or solution in periodontal pockets.

METHODS

Teeth of 12 subjects with at least eight periodontal pockets of ≥5 mm probing depth were isolated with a rubber dam to allow contamination-free access to the pockets. In each subject, three pockets were filled with PVP-iodine gel (10%) and three with PVP-iodine solution (10%). One pocket of each subject without iodine application served as a negative control. The treatment allocation was assigned randomly. Any excess material was removed subsequently. After 1, 5 and 15 min, a paper point was used to collect the sulcus liquid and the concentration of PVP-iodine was chemically determined. In addition, PVP-iodine gel was administered into 12 periodontal pockets immediately after sub-gingival ultrasound debridement and the concentration of PVP-iodine was determined after 1 min.

RESULTS

Descending concentrations of PVP-iodine were determined at 1, 5 and 15 min after the application. No PVP-iodine was found in the pockets serving as negative controls. The mean concentrations of the gel and solution were 6.14 μg/ml and 4.44 μg/ml (1 min; p ≥ 0.028), 3.20 μg/ml and 1.44 μg/ml (5 min; p ≥ 0.126), 0.69 μg/ml and 0.23 μg/ml (15 min; p ≤ 0.019), respectively. In the pockets with previous debridement the mean concentration was 1.68 ± 1.97 μg/ml.

CONCLUSION

The application of PVP-iodine gel in periodontal pockets allows a prolonged remnant effect as compared to that of the solution formula.

Association of pocket epithelial cell proliferation in periodontitis with TLR9 expression and inflammatory response

BACKGROUND/PURPOSE

Inflammatory response is triggered after recognition of microbial ligands by innate receptors such as Toll-like receptors (TLRs) and Nucleotide oligomerization domain (NOD)-like receptors (NLRs). In this study, we examined serial frozen sections of gingival biopsies from patients with gingivitis or periodontitis by immunohistochemical analysis for the topographic expression patterns of selected innate receptors and their association with cell proliferation in clinically healthy and diseased gingival tissues.

METHODS

A total of 19 gingival biopsies were collected from patients at the School of Dentistry, National Taiwan University Medical Center according to approved protocol and with informed consent. The specimens were assigned to either the gingivitis group or periodontitis group after clinical evaluation using gingival index. Frozen sections of gingival biopsies were stained with hematoxylin and eosin for histological evaluation. Serial sections of the same samples were stained with a panel of antibodies for immunohistochemical analysis. Expression of each protein marker was compared in the oral versus the sulcular epithelium of the same section.

RESULTS

Expression of cytokeratin 19 (CK19) was markedly increased in the basement membranes of the oral epithelium and in all layers of the pocket epithelium where it caused evident cell proliferation and migration of sulcular epithelial cells into the lamina propria of periodontitis tissue. TLR4 and the cytoplasmic NLRP3 were expressed in all sections examined regardless of disease state. However, expression of TLR9-, CK19- and collagenolytic matrix metalloproteinase-13 and activated NF-κB subunit p65 was more commonly found in periodontitis tissues than in gingivitis tissues.

CONCLUSION

Activation of TLR9 signaling in the pocket epithelium was highly associated with periodontal inflammation and possibly with loss of tissue integrity. Further studies of mechanisms by which TLR9 signaling is activated in the periodontal epithelium may lead to new strategies for treating periodontitis.

Clinical and microbiological changes after minimally invasive therapeutic approaches in intrabony defects: a 12-month follow-up

OBJECTIVES

This 12-month randomized, controlled trial evaluated the clinical effects and microbiological changes of minimally invasive nonsurgical and surgical approaches for the therapy of intrabony defects.

MATERIALS AND METHODS

Twenty-nine subjects with intrabony defects in single-rooted tooth were randomly assigned to; (1) minimally invasive nonsurgical technique (MINST) or (2) minimally invasive surgical technique (MIST). Quantities of Aggregatibacter actinomycetemcomitans, Tannerella forsythia, and Porphyromonas gingivalis, determined by using real-time PCR, were evaluated at baseline, 3, 6, and 12 months after the treatments. Clinical recordings--probing depth (PD), position of the gingival margin (PGM), and relative clinical attachment level (RCAL)--were obtained at baseline and 12 months post-therapy. The primary outcome variable of the study was RCAL.

RESULTS

Both treatment modalities resulted in an improvement in all clinical recordings, with significant PD reductions (p < 0.05), RCAL gains (p < 0.05), and no change in the PGM (p > 0.05) after 12 months in both MINST and MIST groups. No clinical differences were observed between groups (p > 0.05). Regarding the microbiological outcomes, at the re-examinations, a significant decrease was observed for T. forsythia and P. gingivalis when compared with baseline (p < 0.05) for both treatments. The amount of A. actinomycetemcomitans did not reduced decrease throughout the study (p > 0.05). Intergroup differences in the microbiological assay were not found at any time point (p > 0.05).

CONCLUSIONS

Both MINST and MIST provided comparable clinical results and microbiological changes in the treatment of intrabony defects over 12 months follow-up.

CLINICAL RELEVANCE

This randomized, controlled, parallel trial revealed that both therapeutic modalities may promote clinical and microbiological benefits at 12 months post-therapy.

"What is there in a name?": A literature review on chronic and aggressive periodontitis

The objective of this review is to bring the reader up-to-date on the current understanding of chronic and aggressive forms of periodontitis and the implications for diagnosis and treatment of these diseases. The only difference between chronic periodontitis and aggressive periodontitis with regard to tissue destruction appear to be perhaps the magnitude, sequelae, and control of the response. While there may be some differences in the cellular infiltrate between these two diseases, the molecular mediators and pathologic processes are generally the same.

Locally delivered 0.5% clarithromycin, as an adjunct to nonsurgical treatment in chronic periodontitis with well-controlled type 2 diabetes: a randomized controlled clinical trial

OBJECTIVE

Several epidemiologic studies have identified a greater incidence of periodontitis in patients with type 2 diabetes. Recent developments suggest that local delivery of antimicrobials into periodontal pockets improve periodontal health. The present study was designed to investigate the adjunctive effects of subgingivally delivered clarithromycin (CLM) (0.5% concentration) as an adjunct to scaling and root planing for treating chronic periodontitis in patients with well-controlled type 2 diabetes.

METHODS

Sixty-three patients were categorized into two treatment groups: Group 1, scaling and root planing (SRP) plus 0.5% CLM; Group 2, SRP plus placebo gel. Clinical parameters were recorded at baseline, 1, 2, and 3 months; which included gingival index (GI), sulcus bleeding index (SBI), plaque index (PI), probing depth (PD), and periodontal attachment level (PAL).

RESULTS

Both therapies resulted in significant improvements. Using a subject-based analysis, patients in Group 1 treated with SRP + CLM showed enhanced reductions in PI, GI, SBI, and PD, and gains in PAL (P < 0.001) over a period of 6 months as compared to Group 2.

CONCLUSION

Although both treatment strategies seemed to benefit the patients, the adjunctive use of 0.5% CLM as a controlled drug delivery system enhanced the clinical outcome.

Chemically modified tetracyclines: Novel therapeutic agents in the management of chronic periodontitis

Chronic periodontitis is a complex infection initiated by gram-negative bacteria which destroy the supporting structures of the tooth. Recently, it has been recognized that it is the host response to bacterial infection which causes greater destruction of the connective tissue elements, periodontal ligament and alveolar bone in periodontitis. This has led to the development of various host modulating approaches to target cells and their destructive mediators involved in tissue degradation. Chemically modified tetracyclines (CMTs) are derivatives of tetracycline group of drugs which lack antimicrobial action but have potent host modulating affects. They inhibit pathologically elevated matrix metal loproteinases, pro-inflammtory cytokines and other destructive mediators. Bone resorption is also suppressed due to their combined anti-proteinase and apoptotic affects on osteoblasts and osteoclasts, respectively. Development of resistant bacteria and gastrointestinal toxicity seen with parent tetracyclines is not produced by CMTs. Hence, CMTs are viewed as potential therapeutic agents in the management of chronic diseases like periodontitis that involve destruction of connective tissue and bone.

Host-bacteria crosstalk at the dentogingival junction

The dentogingival junction is of crucial importance in periodontal host defense both structurally and functionally. Oral bacteria exert a constant challenge to the host cells and tissues at the dentogingival junction. The host response is set up to eliminate the pathogens by the innate and adaptive defense mechanisms. In health, the commensal bacteria and the host defense mechanisms are in a dynamic steady state. During periodontal disease progression, the dental bacterial plaque, junctional epithelium (JE), inflammatory cells, connective tissue, and bone all go through a series of changes. The tissue homeostasis is turned into tissue destruction and progression of periodontitis. The classical study of Slots showed that in the bacterial plaque, the most remarkable change is the shift from gram-positive aerobic and facultatively anaerobic flora to a predominantly gram-negative and anaerobic flora. This has been later confirmed by several other studies. Furthermore, not only the shift of the bacterial flora to a more pathogenic one, but also bacterial growth as a biofilm on the tooth surface, allows the bacteria to communicate with each other and exert their virulence aimed at favoring their growth. This paper focuses on host-bacteria crosstalk at the dentogingival junction and the models studying it in vitro.

Evaluation of efficacy of tetracycline fibers in conjunction with scaling and root planing in patients with chronic periodontitis

AIM

The objective of this study was to compare the efficacy of scaling and root planing (SRP) alone versus tetracycline fiber therapy used adjunctively with SRP in the treatment of chronic periodontitis sites in maintenance patients.

MATERIALS AND METHODS

A total of 30 patients with a diagnosis of chronic periodontitis (60 localized chronic periodontitis sites) in the age group of 35 to 55 were selected. None of these patients had received any surgical or non-surgical periodontal therapy and had sites of periodontal pockets measuring 4-7 mm clinically and demonstrated radiographic evidence of moderate bone loss. Two non-adjacent sites in separate quadrants were selected in each patient for monitoring based on criteria that the sites had localized chronic periodontitis. Plaque index (PI) (sillness and loe) and Gingival-bleeding index (GI) (loe and sillness) were measured at baseline and 15(th), 30(th), 60(th), and 90(th)day. Clinical pocket depth (PD) and microbial analysis (MA) were analyzed at baseline and 90(th) day.

RESULTS

At 0 and 3 months adjunctive tetracycline fiber therapy was significantly better in reducing PI, GBI, (P<0.001) than S and RP alone. In comparison, the reduction in the PD was non-significant at 0 and 3 months (P<0.001). The microbial analysis showed significant reduction in Porphyromonas gingivalis and Prevotella intermedia though there was no significant reduction in the Actinobacillus actinomycetemcomitans.

CONCLUSION

Overall, these results indicate that fiber therapy significantly enhanced the effectiveness of SRP in the management of chronic periodontitis.

Levels of Selenomonas species in generalized aggressive periodontitis

BACKGROUND AND OBJECTIVE

To compare the levels of Selenomonas sputigena and uncultivated/unrecognized Selenomonas species in subgingival biofilms from periodontally healthy subjects and from subjects with generalized aggressive periodontitis.

MATERIAL AND METHODS

Fifteen periodontally healthy subjects and 15 subjects with generalized aggressive periodontitis were recruited and their clinical periodontal parameters were evaluated. Nine subgingival plaque samples were collected from each subject and all were individually analyzed for the levels of 10 bacterial taxa, including cultured and uncultivated/unrecognized microorganisms, using the RNA-oligonucleotide quantification technique. Between-group differences in the levels of the test taxa were determined using the Mann-Whitney U-test.

RESULTS

  Subjects with generalized aggressive periodontitis showed significantly higher mean counts of Porphyromonas gingivalis, S. sputigena and the Mitsuokella sp. Human Oral Taxon (HOT) 131 (previously described as Selenomonas sp. oral clone CS002), while higher mean counts of Actinomyces gerencseriae and Streptococcus sanguinis were found in periodontally healthy subjects (p < 0.01). Selenomonas sp. HOT 146 was only detected in the generalized aggressive periodontitis group. In the generalized aggressive periodontitis group, the levels of P. gingivalis and S. sputigena were higher in deep sites (probing depth ≥ 5 mm) than in shallow sites (probing depth ≤ 3 mm) (p < 0.01). Furthermore, in subjects with generalized aggressive periodontitis, sites with probing depth of ≤ 3 mm harbored higher levels of these two species than sites with the same probing depth in periodontally healthy subjects. There were positive correlations between probing depth and the levels of P. gingivalis (r = 0.77; p < 0.01), S. sputigena (r = 0.60; p < 0.01) and Selenomonas dianae (previously described as Selenomonas sp. oral clone EW076) (r = 0.42, p < 0.05).

CONCLUSION

S. sputigena and Mitsuokella sp. HOT 131 may be associated with the pathogenesis of generalized aggressive periodontitis, and their role in the onset and progression of this infection should be investigated further.

Periodontal disease and atherosclerotic vascular disease: does the evidence support an independent association?: a scientific statement from the American Heart Association

A link between oral health and cardiovascular disease has been proposed for more than a century. Recently, concern about possible links between periodontal disease (PD) and atherosclerotic vascular disease (ASVD) has intensified and is driving an active field of investigation into possible association and causality. The 2 disorders share several common risk factors, including cigarette smoking, age, and diabetes mellitus. Patients and providers are increasingly presented with claims that PD treatment strategies offer ASVD protection; these claims are often endorsed by professional and industrial stakeholders. The focus of this review is to assess whether available data support an independent association between ASVD and PD and whether PD treatment might modify ASVD risks or outcomes. It also presents mechanistic details of both PD and ASVD relevant to this topic. The correlation of PD with ASVD outcomes and surrogate markers is discussed, as well as the correlation of response to PD therapy with ASVD event rates. Methodological issues that complicate studies of this association are outlined, with an emphasis on the terms and metrics that would be applicable in future studies. Observational studies to date support an association between PD and ASVD independent of known confounders. They do not, however, support a causative relationship. Although periodontal interventions result in a reduction in systemic inflammation and endothelial dysfunction in short-term studies, there is no evidence that they prevent ASVD or modify its outcomes.

Polymicrobial interactions: impact on pathogenesis and human disease

Microorganisms coexist in a complex milieu of bacteria, fungi, archaea, and viruses on or within the human body, often as multifaceted polymicrobial biofilm communities at mucosal sites and on abiotic surfaces. Only recently have we begun to appreciate the complicated biofilm phenotype during infection; moreover, even less is known about the interactions that occur between microorganisms during polymicrobial growth and their implications in human disease. Therefore, this review focuses on polymicrobial biofilm-mediated infections and examines the contribution of bacterial-bacterial, bacterial-fungal, and bacterial-viral interactions during human infection and potential strategies for protection against such diseases.

Periodontal pathogens affect the level of protease inhibitors in gingival crevicular fluid

In periodontitis, an effective host-response is primarily related to neutrophils loaded with serine proteases, including elastase (NE) and protease 3 (PR3), the extracellular activity of which is tightly controlled by endogenous inhibitors. In vitro these inhibitors are degraded by gingipains, cysteine proteases produced by Porphyromonas gingivalis. The purpose of this study was to determine the level of selected protease inhibitors in gingival crevicular fluid (GCF) in relation to periodontal infection. The GCF collected from 31 subjects (nine healthy controls, seven with gingivitis, five with aggressive periodontitis and 10 with chronic periodontitis) was analyzed for the levels of elafin and secretory leukocyte protease inhibitor (SLPI), two main tissue-derived inhibitors of neutrophil serine proteases. In parallel, activity of NE, PR3 and arginine-specific gingipains (Rgps) in GCF was measured. Finally loads of P. gingivalis, Aggregatibacter actinomycetemcomitans, Tannerella forsythia and Treponema denticola were determined. The highest values of elafin were found in aggressive periodontitis and the lowest in controls. The quantity of elafin correlated positively with the load of P. gingivalis, Ta. forsythia and Tr. denticola, as well as with Rgps activity. In addition, NE activity was positively associated with the counts of those bacterial species, but not with the amount of elafin. In contrast, the highest concentrations of SLPI were found in periodontally healthy subjects whereas amounts of this inhibitor were significantly decreased in patients infected with P. gingivalis. Periodontopathogenic bacteria stimulate the release of NE and PR3, which activities escape the control through degradation of locally produced inhibitors (SLPI and elafin) by host-derived and bacteria-derived proteases.

Antimicrobial peptides and periodontal disease

AIMS

The goal of this review is to identify the antimicrobial proteins in the oral fluids, saliva and gingival crevicular fluid and identify functional families and candidates for antibacterial treatment.

RESULTS

Periodontal biofilms initiate a cascade of inflammatory and immune processes that lead to the destruction of gingival tissues and ultimately alveolar bone loss and tooth loss. Treatment of periodontal disease with conventional antibiotics does not appear to be effective in the absence of mechanical debridement. An alternative treatment may be found in antimicrobial peptides and proteins, which can be bactericidal and anti-inflammatory and block the inflammatory effects of bacterial toxins. The peptides have co-evolved with oral bacteria, which have not developed significant peptide resistance. Over 45 antibacterial proteins are found in human saliva and gingival crevicular fluid. The proteins and peptides belong to several different functional families and offer broad protection from invading microbes. Several antimicrobial peptides and proteins (AMPs) serve as templates for the development of therapeutic peptides and peptide mimetics, although to date none have demonstrated efficacy in human trials.

CONCLUSIONS

Existing and newly identified AMPs may be developed for therapeutic use in periodontal disease or can serve as templates for peptide and peptide mimetics with improved therapeutic indices.

Does routine analysis of subgingival microbiota in periodontitis contribute to patient benefit?

In clinical periodontology it is common practice to sample subgingival plaque from periodontitis patients and to search for the presence of alleged periodontal pathogens using routine laboratory techniques such as culture, DNA-DNA hybridization or real-time PCR. Usually, special attention is given to the recognition of 'red complex' microorganisms and to Aggregatibacter actinomycetemcomitans. Recently, molecular open-ended techniques have been introduced which are distinct from the more 'classical' approaches in that they do not preselect for certain species. In this study, we investigated to what extent the outcome of these techniques has changed our insight into the composition of the subgingival microbiota and whether this has consequences on clinical decision making. The open-ended approaches showed that the composition of subgingival plaque is much more complex than previously thought. Next to the 'classical' putative periodontal pathogens, several non-culturable and fastidious species are now recognized as being associated with periodontitis, thus enlarging the group of suspected periodontal pathogens. We conclude that routine analyses of subgingival plaque in the clinic are not necessarily of benefit to the patient.

RNA-oligonucleotide quantification technique (ROQT) for the enumeration of uncultivated bacterial species in subgingival biofilms

Approximately 35% of the species present in subgingival biofilms are as yet uncultivated, so their role in periodontal pathogenesis is unknown. The aim of the present study was to develop a high throughput method to quantify a wide range of cultivated and uncultivated taxa in subgingival biofilm samples associated with periodontal disease or health. Oligonucleotides targeting the 16S ribosomal DNA gene were designed, synthesized and labeled with digoxigenin. These probes were hybridized with the total nucleic acids of pure cultures or subgingival biofilm samples. Target species included cultivated taxa associated with periodontal health and disease, as well as uncultivated species, such as TM7 sp. OT 346, Mitsuokella sp. OT 131 and Desulfobulbus sp. OT 041. Sensitivity and specificity of the probes were determined. A Universal probe was used to assess total bacterial load. Sequences complementary to the probes were used as standards for quantification. Chemiluminescent signals were visualized after film exposure or using a CCD camera. In a pilot clinical study, 266 subgingival plaque samples from eight periodontally healthy people and 11 patients with periodontitis were examined. Probes were specific and sensitivity reached 10(4) cells. Fusobacterium nucleatum ss. polymorphum and Actinomyces gerencseriae were the most abundant cultivated taxa in clinical samples. Among uncultivated/unrecognized species, Mitsuokella sp. OT 131 and Prevotella sp. OT 306 were the most numerous. Porphyromonas gingivalis and Desulfobulbus sp. OT 041 were only detected in patients with periodontitis. Direct hybridization of total nucleic acids using oligonucleotide probes permitted the quantification of multiple cultivated and uncultivated taxa in mixed species biofilm samples.

Detection of periodontal bacteria in atheromatous plaque by nested polymerase chain reaction

BACKGROUND

In recent years, increasing evidence regarding the potential association between periodontal diseases and cardiovascular diseases has been identified. The available evidence underlines the importance of detecting periodontal pathogens on atheromatous plaque as the first step in demonstrating the causal relationship between the two conditions. The main aim of this investigation is to detect periodontitis-associated bacteria from carotid artery atheromatous plaque from patients who received an endarterectomy using strict sample procurement and laboratory procedures.

METHODS

Atheromatous plaque from endarterectomies from carotid arteries were scraped and homogenized, and bacterial DNA was extracted. To obtain a representative concentration of amplicons, two amplifications of the bacterial 16S ribosomal-RNA gene were carried out for each sample with universal eubacteria primers by a polymerase chain reaction (PCR). A nested PCR with specific primers for the target bacteria was performed next. Statistical tests included the χ(2) test.

RESULTS

Forty-two atheromatous plaque were analyzed. All of them were positive for ≥1 target bacterial species. The bacterial species most commonly found was Porphyromonas gingivalis (78.57%; 33 of 42), followed by Aggregatibacter actinomycetemcomitans (previously Actinobacillus actinomycetemcomitans) (66.67%; 28 of 42), Tannerella forsythia (previously T. forsythensis) (61.90%; 26 of 42), Eikenella corrodens (54.76%; 23 of 42), Fusobacterium nucleatum (50.00%; 21 of 42), and Campylobacter rectus (9.52%; four of 42). The simultaneous presence of various bacterial species within the same specimen was a common observation.

CONCLUSION

Within the limitations of this study, the presence of DNA from periodontitis-associated bacteria in carotid artery atheromatous plaque retrieved by endarterectomy is confirmed.